As an example of a braking device for a vehicle for controlling a friction braking force applied to a vehicle, the braking device for a vehicle disclosed in a Patent Publication No. JP2012-16984 A has been known. This braking device includes a master cylinder device which generates a master hydraulic pressure by driving the output piston which is driven by applying the servo pressure generated based on the pressure of the pressure source (accumulator), under the state that the input piston and the output piston are separated in the in-between pistons chamber.